Exoskeleton. The outer skeleton; all shells are exoskeletons. 



Exotic. Foreign. 



Exserted. Brought out. 



Expanded. Spread out, as the lip of some shells. 



Falcate. Scythe-shaped. 



Fasciculus. A little bundle. 



Ferruginous. Of the color of iron. 



Filament. A slender, thread-like object. 



Filiform. Thread-like. 



Fissure. A cleft or cut. 



Flagellate. Animals with a flagellum or lash. 



Flavescent. Yellowish. 



Flexuous. Formed in a series of curves or turnings, as the columella in some 

 shells. 



Flocculent. Clinging together in bunches. 



Fluviatile. Living in running streams. 



Foliaceous. Leaf-like. 



Fuscous. Dark brown in color. 



Fusiform. Thick in the middle and tapering at each end. 



Gaping. Opening or spreading, as the valves of some Pelecypods. 



Gelatinous. Like jelly, as the eggs of some mollusks. 



Gibbous. Very much rounded, as the whorls in some snails. 



Glandular. Like a gland. 



Globose. Hounded. 



Granulated. Covered with little grains. 



Gravid. A female mollusk (as Unio) with ovaries distended with young. 



Gregarious. Living in colonies. 



Gular. Relating to the windpipe or palate. In mollusks, referring to the inner- 

 most part of the aperture. 



Habitat. Locality of a species. 



Hamiolymph. Molluscan blood. 



Haliotoid. Ear-shaped. 



Heliciform. In form like Helix. 



Hemispherical. Half a sphere. 



Herbivorous. Subsisting upon vegetable food. 



Hermaphrodite. Having the sexes united in the same individual. 



Hibernation. The act of hibernating or going to sleep for the winter months. 



Hirsute. Covered with hairs, as some snails. 



Hispid. Same as hirsute. 



Homologous. Having the same position or value, as the wing of a bird and 

 of a bat. 



Hyaline. Glassy. 



Imperforate. Not perforated or umbilicated. 



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